Activate:

Windows 8.1 Single Language;
Windows 8.1 Core;
Windows 8.1 Core N;
Windows 8.1 Pro WMC;
Windows Embedded 8.1 Industry Pro;
Windows Server 2012 R2 Standard;
Windows Server 2012 R2 Datacenter.
It is based on KMS Server Service from mikmik38 (MDL).

Changelog:

Added support to activate OEM editions: “Windows 8.1 Single Language with Bing�,
“Windows 8.1 with Bing� and “Windows 8.1 Pro for Education�